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Abstract:

The present invention is directed to a polymeric bag having a reduced
gauge portion extending generally across the width of the bag, wherein
the reduced gauge portion allows that area of the polymeric bag to be
stretched more easily. This invention is especially advantageous in the
context of drawstring trash bags wherein the reduced gauge portion
encompasses the hems.

Claims:

1. A thermoplastic bag comprising: a first panel and a second panel, the
first panel and second panel joined along a first side edge, a second
side edge, and a bottom edge, a top edge of the first panel and second
panel defining an upper opening of the bag, the first panel having a
normal thickness, wherein the first panel comprises a reduced gauge
portion, the reduced gauge portion of the first panel having a thickness
that is less than the normal thickness of the first panel.

2. The thermoplastic bag of claim 1, further comprising: the reduced
gauge portion of the first panel extending substantially across a width
of the first panel.

3. The thermoplastic bag of claim 2, further comprising: the reduced
gauge portion of the first panel having a substantially uniform height.

4. The thermoplastic bag of claim 1, further comprising: the thickness of
the reduced gauge portion of the first panel is less than or
approximately equal to 80% of the normal thickness of the first panel.

5. The thermoplastic bag of claim 4, further comprising: the thickness of
the reduced gauge portion of the first panel is less than or
approximately equal to 50% of the normal thickness of the first panel.

6. The thermoplastic bag of claim 1, further comprising: a first hem
provided in the first panel and a first drawstring contained within the
first hem, wherein the reduced gauge portion of the first panel
substantially includes all of the first hem.

7. The thermoplastic bag of claim 6, further comprising: the first
drawstring is elastic.

8. The thermoplastic bag of claim 6, further comprising: wherein the
reduced gauge portion of the first panel further includes an area of the
first panel below the first hem.

9. The thermoplastic bag of claim 1, further comprising: the second panel
having a normal thickness, wherein the second panel comprises a reduced
gauge portion, the reduced gauge portion of the second panel having a
thickness that is less than the normal thickness of the second panel.

10. The thermoplastic bag of claim 9, further comprising: a first hem
provided in the first panel and a first drawstring contained within the
first hem, wherein the reduced gauge portion of the first panel
substantially includes all of the first hem, a second hem provided in the
second panel and a second drawstring contained within the second hem,
wherein the reduced gauge portion of the second panel substantially
includes all of the second hem.

11. The thermoplastic bag of claim 10, further comprising: the first
drawstring and the second drawstring are elastic.

12. The thermoplastic bag of claim 10, further comprising: wherein the
reduced gauge portion of the second panel further includes an area of the
second panel below the first hem.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] Not applicable.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to improvements in the construction
and manufacture of polymeric bags. In particular, the present invention
relates to improvements to trash bags.

[0004] 2. Description of the Related Art

[0005] Polymeric bags are ubiquitous in modern society and are available
in countless combinations of varying capacities, thicknesses, dimensions
and colors. The bags are available for numerous applications including
typical consumer applications such as long-term storage, food storage,
and trash collection. Like many other consumer products, increased demand
and new technology have driven innovations in polymeric bags improving
the utility and performance of such bags. The present invention is an
innovation of particular relevance to polymeric bags used for trash
collection.

[0006] Polymeric bags are manufactured from polymeric film produced using
one of several manufacturing techniques that are well-known in the art.
However, the two most common manufacturing methods for creating polymeric
film are blown-film extrusion and cast-film extrusion. Both blown-film
extrusion and cast-film extrusion offer certain advantages versus the
other. The ultimate selection of a method of manufacture is often driven
by considerations such as the desired properties for the final product as
well as by financial considerations.

[0007] In both blown-film extrusion and cast-film extrusion, an extruder
is used to push molten polymeric material through a die. In the case of
blown-film extrusion, the film during processing is tubular in shape. In
cast-film extrusion, the film during processing is substantially flat.
Certain dies also allow for the manufacture of polymeric films having
multiple layers co-extruded through a single die. An early die designed
to produce multi-layer blown-film tubes is described in U.S. Pat. No.
4,185,954 entitled Die for Extruding Tubes Composed of Plurality of
Layers. Furthermore, other types of co-extrusion dies are available which
allow for different polymer blends to be extruded through a single die to
provide distinct sections across the width, or circumference, of the
extruded film. Such dies, for example, may be used with polymer blends
having different color additives to provide stripes in the extruded
blown-film.

[0008] As previously stated, the present invention relates to polymeric
trash bags, which are available in several popular configurations such as
drawstring trash bags and wave-cut trash bags, the latter of which have
two or more flaps extending from the top of the bag. Both drawstring and
wave-cut trash bags are popular among consumers and, given their
popularity, recent innovations have attempted to improve the bags'
performance.

[0009] One common complaint, which is applicable to many different types
of trash bags, revolves around the tendency of the trash bag to fall into
the trash can during use. Specifically, the top of the trash bag, which
is placed over the top of the can, often has a tendency to fall into the
trash can as the weight of the trash pulls the bag downward into the can.

[0010] To address this issue, certain trash bags now provide features
intended to enhance the ability of the bag to "grip" the outside of the
trash can near the top of the trash can. With respect to drawstring trash
bags, elastic drawstrings have been introduced which stretch outward and
retract in order to grip the outside of a trash receptacle. However, the
physical properties and strength of the panels comprising the trash bags,
specifically the area near the top of the bag at or around the hem area,
can make it difficult to stretch the mouth of the bag over the perimeter
of the trash receptacle.

[0011] One prior art attempt to address this problem is to provide
perforations or notches near the upper corners of the bag thereby
allowing the ends of an elastic drawstring to be separated from the bag
proper and stretched over and around the upper opening of a trash
receptacle. However, the perforations or notches result in large openings
at the top of the bag when it is closed. Additionally, when compared with
traditional drawstring trash bags, the perforations and/or notches in the
bag can increase the risk that tears will propagate away from the cutouts
when stress is placed on the bag.

[0012] In view of the foregoing, it would be desirable to provide a trash
bag that is easier to extend over the upper opening of a trash can, keeps
the structural integrity of the bag intact, and overcomes challenges of
the prior art. Additionally, it would also be desirable to provide a
trash bag that effectively grips trash cans. The present invention
addresses these and other needs.

SUMMARY OF THE INVENTION

[0013] In one embodiment of the present invention, a trash bag is
comprised of a first panel and a second panel joined along a first side
edge, a second side edge, and a bottom edge. The top edge of the first
panel and second panel defines an upper opening of the bag. The first
panel has a normal thickness and further comprises a reduced gauge
portion. The reduced gauge portion of the first panel has a thickness
that is less than the normal thickness of the first panel. In some
embodiments of the present invention, the reduced gauge portion of the
first panel extends substantially across a width of the first panel.
Additionally, the reduced gauge portion of the first panel may have a
substantially uniform height.

[0014] In certain embodiments of the present invention, the thickness of
the reduced gauge portion may be less than or approximately equal to 80%
of the normal thickness of the first panel. Furthermore, in some
embodiments of the present invention, the thickness of the reduced gauge
portion may be less than or approximately equal to 50% of the normal
thickness of the first panel. Additionally, the second panel may also
have a normal thickness with a reduced gauge portion of the second panel
having a thickness that is less than the normal thickness of the second
panel.

[0015] In some embodiments of the present invention, a first hem is
provided in the first panel with a first drawstring contained within the
first hem. Additionally, a second hem may be provided in the second panel
with a second drawstring contained within the second hem. In some
embodiments, the first drawstring may be elastic or both the first and
second drawstring may be elastic. Furthermore, in such embodiments, a
reduced gauge portion of the first panel may be provided that includes
substantially all of the first hem and may further include an area of the
first panel below the first hem. Similarly, a reduced gauge portion of
the second panel may be provided that includes substantially all of the
second hem and may further include an area of the second panel below the
second hem.

BRIEF DESCRIPTION OF THE RELATED DRAWINGS

[0016] A full and complete understanding of the present invention may be
obtained by reference to the detailed description of the present
invention and certain embodiments when viewed with reference to the
accompanying drawings. The drawings can be briefly described as follows.

[0017] FIG. 1 provides a perspective view of a first embodiment of the
present invention.

[0018]FIG. 2 provides an elevation view of a panel used to construct the
first embodiment of the present invention.

[0019] FIG. 3 provides a perspective view of a second embodiment of the
present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The present disclosure illustrates several embodiments of the
present invention. It is not intended to provide an illustration or
encompass all embodiments contemplated by the present invention. In view
of the disclosure of the present invention contained herein, a person
having ordinary skill in the art will recognize that innumerable
modifications and insubstantial changes may be incorporated or otherwise
included within the present invention without diverging from the spirit
of the invention. Therefore, it is understood that the present invention
is not limited to those embodiments disclosed herein. The appended claims
are intended to more fully and accurately encompass the invention to the
fullest extent possible, but it is fully appreciated that certain
limitations on the use of particular terms are not intended to
conclusively limit the scope of protection.

[0021] Referring initially to FIG. 1, a perspective view of drawstring
trash bag 100 is shown according to one embodiment of the present
invention. The drawstring trash bag comprises a first panel 102 and a
second panel 104, each panel being substantially rectangular in shape.
The first panel 102 and second panel 104 are coupled along a first side
edge 106, a second side edge 108, and a bottom edge 110 of the respective
panels 102 and 104. In some embodiments, the first panel 102 and second
panel 104 may be formed from a single piece of polymeric film, folded to
define a bottom edge 110 and sealed along the first side edge 106 and
second side edge 108.

[0022] The unsealed top edge 112 of the respective panels 102 and 104
defines the upper opening of the drawstring trash bag. A pair of
drawstrings 140 are disposed within hems 142 located proximate the top
edge 112 of the respective first panel 102 and second panel 104. The
drawstrings 140 may be traditional high-density polyethylene drawstrings
or, in some embodiments, may be elastic drawstrings. The drawstrings are
generally loose within the hems 142 and sealed near the upper corners of
the drawstring trash bag 100 by short seals 120 and 122. Therefore, when
the drawstrings 140 are pulled through the drawstring cutouts 144 of the
bag 100, the respective upper corners of the bag 100 are pulled together,
facilitating closure of the bag.

[0023] In the depicted embodiment of FIG. 1, the panels 102 and 104 of the
drawstring trash bag 100 are primarily comprised of a polymer blend which
generally comprises linear low density polyethylene (LLDPE) although
other polyethylenes may be utilized as the primary component such as high
density polyethylene (HDPE) or low density polyethylene (LDPE).
Typically, the LLDPE comprises at least 80% of the polymer blend. The
remaining 20% of the polymer blend may comprise additives to provide
color for the final product, increased resistance to blocking, odor
control, or other properties.

[0024] To facilitate the drawstrings 140 in being stretched over certain
trash receptacles while still keeping the structural integrity of the bag
intact, a reduced gauge portion 150 generally extends across the width of
the drawstring trash bag 100 and may generally encompass the hems 142 and
may also encompass a small area below the hems 142 as well. The reduced
gauge portion 150 has a thickness, or gauge, that is less than the
remainder of the trash bag panels 102 and 104. The thickness of the
remainder of the trash bag panels 102 and 104 may be referred to herein
as the normal gauge or normal thickness of the respective trash bag
panels 102 and 104. However, it is understood that the thickness of thin
polymeric films may vary and that certain variations in thickness may be
expected. Therefore, the gauge and thickness of a polymeric film is
usually expressed in terms of an average thickness across a certain area.

[0025] In a typical embodiment of the present invention as shown in FIG.
1, the reduced gauge portion 150 may have a thickness that is less than
or equal to 80% of the normal thickness of the trash bag panels 102 and
104. As an example, in a certain embodiment, the trash bag panels 102 and
104 may have a normal thickness of 1.0 mil while the thinner portion 150
may have a thickness of approximately 0.8 mil. Furthermore, it is
contemplated that in certain other embodiments, the reduced gauge portion
150 may have a thickness equal to or less than 50% of the normal
thickness of the trash bag panels 102 and 104. Compared to a similar
trash bag known in the prior art which has substantially uniform
thickness, the reduced thickness of the reduced gauge portion 150
provides less resistance when stretching the mouth of the trash bag 100
over certain trash receptacles.

[0026] In some embodiments of the present invention, the reduced gauge
portion 150 may be comprised of the same polymer blend as the remainder
of the trash bag panels 102 and 104. For example, in many embodiments of
the present invention the trash bag panels 102 and 104 may be comprised
primarily of linear-low density polyethylene (LLDPE), which typically
makes up over 80% of the polymer blend used for the trash bag panels 102
and 104. IN certain embodiments, the reduced gauge portion 150 may
comprise the same polymer blend, comprising at least 80% of LLDPE.
However, in other embodiments of the present invention, the polymer blend
of the reduced gauge portion 150 may be a modified polymer blend,
different from the polymer blend used for the trash bag panels 102 and
104. The modified polymer blend may have a lower modulus of elasticity
than the remainder of the panels 102 and 104 facilitating the reduced
gauge portion 150 of the drawstring trash bag 100 to be stretched over
the outside of a trash receptacle. Additionally, the modified polymer
blend may provide greater elastic recovery improving the grip of the
drawstring trash bag 100 on the outside of the trash receptacle after
being placed over it. It is contemplated that several different polymers
may be used in the modified polymer blend, including but not limited to,
linear low density polyethylene (LLDPE), low density polyethylene (LDPE),
ethylene-vinyl acetate (EVA), ethylene-acrylic acid (EAA), very low
density polyethylene (VLDPE), and ultra low density polyethylene (ULDPE).
As an example, in some embodiments of the present invention, a modified
polymer blend of the reduced gauge portion 150 may comprise at least 20%
ULDPE or VLDPE. However, in certain preferred embodiments, the modified
polymer blend may have at least 50% ULDPE or VLDPE.

[0027] Referring now to FIG. 2, the first panel 102 is depicted to better
illustrate the first panel 102 made with a reduced gauge portion 150. The
reduced gauge portion 150 is shaded to illustrate the portion of the
first panel 102 which is thinner than the normal thickness for the
remainder of the first panel 102. In the depicted embodiment, the reduced
gauge portion 150 of the first panel 102 encompasses the entire area of
the hems 142 and extends slightly below the hem 142 as well. A person of
ordinary skill in the art would understand that FIG. 2 illustrates the
first panel 102 wherein the drawstring cutout 144 has been provided but
before providing a drawstring 140. After providing the drawstring 140,
the upper portion of the first panel 102 would be folded downward over
the drawstring 140 to form the hem 142 as shown in FIG. 1.

[0028] Referring now to FIG. 3, another embodiment of the present
invention is depicted. The embodiment depicted in FIG. 3 is an improved
drawstring bag 300 similar to the drawstring trash bag 100 of FIG. 1.
Like the embodiment of FIG. 1, the reduced gauge portion 150 includes the
hems 142 and extends slightly below the hems 142. However, in this
improved drawstring trash bag 300, a first inner short seal 320 and a
second inner short seal 322 are additionally provided to seal the
drawstrings 140 and panels 102 and 104 together. The first inner short
seal 320 and second inner short seal 322 effectively reduce the width of
the upper opening of the improved drawstring bag 300.

[0029] As previously noted, the specific embodiments depicted herein are
not intended to limit the scope of the present invention. Indeed, it is
contemplated that any number of different embodiments may be utilized
without diverging from the spirit of the invention. Therefore, the
appended claims are intended to more fully encompass the full scope of
the present invention.